Means for protecting getter materials have long been known in the art. Barium, when used as a metal in its elemental form was placed in a sheath of protective metal which guarded against attack by atmospheric gases. With the development of more sophisticated evaporated getter devices the very nature of the alloys used, such as BaAl.sub.4, gave inherent protection since the alloys did not react with atmospheric gases. However such devices have to be heated to about 800.degree.-1200.degree. C. to cause release of barium metal and thus develop their reactive ability.
Non-evaporated getters also have a protection mechanism whereby they form protective layers on the surface of the gettering material. Nevertheless their protective layer must be removed by a thermal treatment, or by activation, at high temperature for a given time to enable the surface to become clean and to act as a gas scavenger. Even with low temperature activatable getter materials, this temperature still has to be raised to about 400.degree. C., for the material to become active.
Protection has been afforded to these non-evaporated getters, after suitable activation, by the use of rupturable containers, such as in U.S. Pat. No. 4,124,659 to della Porta et al. or by the use of glass phials as in U.S. Pat. No. 4,938,667 to della Porta, the entire disclosures of both which are incorporated herein by reference.